Suspension potential transformer



Feb. 28, 1933. G. E. JANSSON SUSPENSION POTENTIAL TRANSFOHMER Filed Feb. 27, 1951 2 Sheets-Sheet Feb. Y28, 1933. G. E. JANSSON SUSPENSION POTENTIAL TRANSFORMER Filed Feb.` 27, 1931 2 Sheets-Sheet Patented Feb. 28, 1933 UNITED STATES PATENT OFFICE GUSTAV E. JANSSON, OF ATLANTIC, MASSACHUSETTS, ASSIGNOR- TO CONDIT` ELEC- TRICAL MANUFACTURING CORPORATION, 0F HYDE PARK, MASSACHUSETTS, A COR- PORATION 0F MASSACHUSETTS SUSPENSION POTENTIAL TRANSFORMER Application filed February 27, 1931. Serial No. 518,725.

This invention relates to improvements inv transformers and has for its object the provision of a voltage transformer which makes possible the connection of low tension instruments and other power consuming` control apparatus to a high tension power system, and particularly to a high tension transmission line, without resorting to the costly constructions of the usual high tension electromagnetic potential transformer.

The primary Winding of an electromagnetic transformer must be connected electrically to the high tension line and consequently must be insulated both from its core strueture andthe secondary winding by insulation capable of withstanding the full line voltage. lith modern transmission voltages in the order of 110,000 to 220,000 volts, the insulation necessary adequately to insulate the line voltages becomes very bulky and the tran?- former is accordingly expensive.

In accordance with this invention a potential transformer of the usual electromagnetic .type is employed, the windings of which insulated only for a relatively moderate voltage which presents no difficult problems of insulation, and the primary winding of the transformer is connected electrically with the high tension line to be controlled through a plurality of interposed serially electrically connected voltage impedance units which are mechanically connected in a string and are suspended, as from the hi gh tension line, by means of suspension type insulators which are interposed between and mechanically connect the adjacent units. As thus arranged the insulation between the units is in series and although the insulation between any two adjacent units is insufficient to withstand the potential of the line, the combi ned insulation between all the units is sufficient to insulate the transformer unit, which is the most remote unit of the string, from the high tension line. The provision of a multi-unit suspension type voltage transformer as above set forth constitutes one of the objects of this invention.

It is a further object of the invention to provide a voltage transformer o. this type wherein the voltage drop between the high tension line and the control circuit is obtained by means of a plurality of serially electrically connected react-ance units the core structures of which are mechanically connected and are insulated from each other by suspension type insulators.

A still further object of the invention is to provide a. voltage transformer of the above type in which certain of the reactance units are wound of material having high electrical resist-ance.

A yet further object is the. provision of an impedance unit for a multi-unit suspension type voltage transformer having provision whereby a varying number of standard units may be connected together in series to vary the insulation between the high tension line and the low tension control circuit. A yet further object is the provision of an improved construction for a secondary transformer which will be reliable in service and cheap to manufacture and inst-all.

A further object is generally to improve the methods and apparatus for deriving relatively small amounts of power at low tension from high tension systems.

Fig. l is a side elevation partly in section of a voltage transformer embodying the invention.

Fig. 2 is a plan view of one of the reactance units of Fig. l.

Fig. 8 is a section through the upper leg of a magnetic core taken on line 3 3 of Fig. 2.

Fig. 4 is a sectional elevation of a moditied construction for the rcactance units.

Fig. 5 is a side elevation partly in section of another form of the invention in which the units thereof are enclosed in compound filled housings.

Fig. 6 is a plan view of a. unit of Fig. 5.

The voltage transforming device embodying the invention includes a plurality of serially electrically and mechanically connected electromagnetic units arranged as a suspension string, one end unit of which is adapted to be connected electrically with a high tension line to be controlled and the yother and remote unit of which is adapted to be connected to a low tension control circuit. The several units of the device are mechanically connected by means of interposed insulating members which also consti# tute means for electrically insulating adjacent units from each other7 a suitable number of units being employed so that the coinbined insulation between the several units will be suliiicient to insulate the most remote unit from the high tension line.

The lowermost unit of the string comprises an electromagnetic transformer. is shown in Fig. l7 said transformer includes a laminated core member l0 which constitutes a closed-magnetic circuit on one Leg of which the primary and secondary windings 12 and..

14E are supported in insulating relation with said core structure and with each other.V VSaid windines l2 and Vld are insulated from said V toni le@l 2O orP said core.

- provided with lateral projections 26 whichl kflange 24e oit sidep'late 22, whereby to carry said leads below insulate them troni theV its lower face into which the outer tube 18 ez'tends? thus providing a core l() by means of spaced concentric inner and outer insulating tubes 16 and 18 which surround the `right hand core leg and whichVV by the bot- Y.

are supported at extend beyond said core structure beneath the bottoni ends of said tubes 16 and i8 and constitute a support therefor. Said secondary winding if. is located witl `n the annular space between and intermediate theelength of said tubes and has its terminal leads 28 extended downwardly through said annular space and through a bushing 8O which is car; ried byand insulates said leads from the core structure. Said inner'tnbe has an integral outstanding cape 3Q its Lippe-rend which is formed with an lannular recess 3l in vthe upper end of weatherproof closure vfor the annular space 10i. zitje@ Q i mtb .18'. between saitaces. Mair. ou ci u e i is provided with a siniilar Vcape 86 below the capey 82 which overhangs the primary windsion primary winding and the core structure.

g l2 andV also serves to greatly increase the surface leakage path between the high ten- Said primaryV winding also enclosed in a weatherprool2 housing which includes the outer insulating cylinder 38 which surrounds said winding and a frustro-conical cylinder 40 Vwhich cveriies said winding and said cyl- Vinder 38. rllhe outer insulating tube i8 is 4vformed with a downwardly and outwardly directed peripheral flange l2 located beneath thecape 86 which Voverlies the top edge of cylinder 1li).v The primary winding is thus protected from the weather. A terminal lead Y .44' oli said primary vwinding is extended down- 4wardly within the housing cylinder 38 and through an insulating bushing 46 which is carried by the flange 2li of a side plate 22 of the core structure and is carried to a ground connection, not shown. Y Vl`he other lead 48 of said Vwinding is brought out through a downwardly inclined passage 50 in the cylinder 38 adjacent the Lipper end thereof and is extended upwardly and is connected electrically/"to `the next upper unit which will be hereinafter described.

The primary and secondary windings of the transformer unit additionally protected against'ing'ress ofinoisture by means ot a normally solid insulating compound which is introduced in a heated and lluid Vcondition into the annular spaces 52 and -fl above and below said primary winding and also into the spaces 56 and 58 above and below said secondary winding. The upper leg` of the corev structure is `also Ypfovidec with side plates 60 similar tothe plates 22 having outstanding flanges 6l and bolts '23 extend through said side plates 60 the laininations therebetween and secure said plates securely to the core structure., Y y

The primary winding l2 or the transioriner unit above described is not intended to he insulated from the core structure and from the secondary winding lil for the total voltage of thehigh tension line but is ad pted to be insulated only for some small part of said high tension line voltage, which insulating can be accomplished without great dilliculty. For example, `the insulation of said primary winding1QI may bedesigned for 13,509 volts which be Vreadily insulated number of which will be increased with inl creasing line voltage; Said units can be reactive units, where the impedance is mainly core structure G2 which issiinilar in construction to the core l0 of said transformer unit and which includes upper and lower side plates 64 and 6G having oppositely and ontL wardly extended iianges 68 and 70. rlhe similar legs, as the right hand legs, of said be sistance units7 where cores are each surrounded by an insulating tube 72 having an ALipper outstanding cape 74 which overhangs a multi-turn reactance winding 7 6 and provides an extensive surface ereepage path between the upper high tension end of said winding and the core. An outer cylindrical housing '78 surrounds said reactance winding and extends upwardly from the lower leg of said core to a point beneath the cape 74. An insulating cylinder formed of bakelite or other fibrous insulating material has a downwardly and outwardly flared skirt 79 which overhangs the upper end of said cylindrical insulating tube 7 8 and has its inner end extended upwardly within a recess 80 beneath said cape 7 4, thus to provide a weatherproof closure for the annular space between the tube 72 and housing 7 8 which is occupied by said winding 76. A body of normally solid insulating compound 82 is introduced into the annular space below said winding 76 while in a heated and fluid state whereby to seal the space and prevent access of moisture to the winding. The upper terminal leads 86 of said reactor windings are brought out through downwardly inclined passages 88 in the insulating cylinder 78 and extend upwardly for connection with the next upper unit. The lower leads 90 of said windings are electrically connected with the core 62 and with the lead 86 of the next lower unit by means of a double lug connector 92 which is secured to the core 62 by means of the clamping bolt 94.

Each impedance unit is adapted to be thus connected in series with the adjacent units, a suflicient number of impedance units being employed vto provide the required drop between the high tension line and the primary vwinding 14 ofthe lowermost electromagnetic transformer unit. The uppermost im` pedance unit has its upper terminal lead 86 electrically connected with the high tension line and the lowermost impedance unit has its lower terminal lead 90 electrically connected with the transformer primary winding 12.

Means are provided to insulate the core structures of the several units one from another which means also constitutes the mechanical support for the units. To this end a suspension type insulator 96 is provided between and spaces apart the adjacent units. Said insulators may be of the usual suspension cape type known as strain insulators which are provided with a central outstanding cape 98. Each of said insulators also has a metal attaching cap 100 above the cape thereof which is provided with upstanding attaching ears 102 and with a lower dependring metal tongue 104 below the ca pe which is arranged in a vertical plane at right angles to the ears 102. Said tongue 104 is pivotally connec ed to the core structure of the adjacent lower unit by means of an attachingclamp having complemental clamping members 106. As best shown in Fig. 3 said clamping members 106 have upstanding spaced and parallel lugs 108 between which the depending tongue 104 of the insulator is loosely received and is pivoted on a pin 110 which extends through said lugs and the tongue. Said clamping portions are further provided at their lower end with integral depending flanges comprising the vertical portions 112 which overlie the extended ends of the flanges 68 of the core structure and inwardly reilexed horizontal portions 114 which extend beneath said flanges 68, thus to provide opposed horizontal recesses 116 in which the flanges of the opposite side platesl 64 are closely received. A clamping bolt 118 extends through the body portions of said attaching members 106 and clamps said members fixedly in position on the core structure while permitting free pivotal movement of the tongue 104 relative to the lugs 108. The insulator 96 is secured to the unit above it by means of a T-shaped attaching member 120 which comprises a plate 122 that is secured to the lower outstanding fianges 7 0 of the core structure by means of bolts 1211- and an integral depending flat tongue 126 which lies in a plane normal to the vertical plane of the core structure and is received between and is pivotally connected with the ugsta-nd ing ears 102 of said insulator cap by means of a pivot pin 127. As thus arranged the counection between two adjacent impedance units permits pivotal movement of the connected units in two vertical planes which are normal to each other and which prevents unnecessary strain on the attaching members due to laterally applied wind forces. The attaching members 120 and the clamping members 106 are secured to the flanges 68 and 70 of the lower and upper core structures at a point which is in a vertical plane including the center of mass of the units, so that the connected units hang in vertical alignment.

Figs. 5 and 6 illustrate another embodiment of the invention in which the impedance units and the lower transformer unit are enclosed within compound filled metallic housings. As here shown, the core structures 10u. and 62a of the transfo 1mer and impedance units are each enclosed within a housing comprising a generally cylindrical side wall 128, open at the top and bottom, having a cover 130 which provides a weatherproof closure for the open top thereof. Said cover accordingly has a depending peripheral liange 132 which overlies the outer surface of said casing wall 128 and which is permanently secured thereto as by soldering or welding. The magnetic core structure 10a and 620, of said transformer and impedance units are located eccentrically within the housing and the housings are provided with outstanding vertical extensions, or channels, 133 into which the core projects, thus to reduce* the volume of the housing. Said core structures, which may be'identical in construction, include a plurality of thin laminationswhich "5; areY firmly gripped between pairs or" side plates 60a and 22a which are disposed on opposite sides of the upper and lowerk legs respectively of said core laminations,'by bolts 23a located at the corners of said cores. Said plates also have oppositelyand outwardly eX- upon the top of cover 180 transversely of the Vare screw-threaded into rectangular tended iianges 61a and 24a at their top and bottom edges respectively. rlhe cover 1S() is adapted to be lixed to the flanges 61a and the securing` means therefor constitutes the lower 150i a pair or pivot-ally connected attaching members 184 and 185 for interconnecting'the core structures of adjacent units.

Said lower attaching member 184 comprises a generally elongated bloclr which rests core and overlying the iianges 61av thereor.V Said block is provided with an elongated recess 186 inits lower race adjacenrthe cover into which project integral upstanding necks `188 oi said cover 186. Said neclrs, which are preferably formed by expressing the material ofV said cover, are provided with vertical pas-V sages 139 to receive bolts 140 which pass through said block and the lianges 61a and beneath said flanges. T he attaching meinbers 134 are provided with central and spaced upstanding lugs 144Vwhich,arepivotally conn nnected by a pin 146 'to a .depending tongue "148. or" said upper attaching member 185 which is received between said lugs 144. @ne

Y or the clamping bolts 28a, as the lower lefthand corner bolt is extended outwardlyV through the housing, whereby to connect Ythe "housing and core at t iis point and relieve the attaching member 134 of strain due to the eccentric attachment of the core thereto( The upper attaching member ldconstitutes the lower attaching pin of a cape insulator' 86a,

one of which is interposed between adjacent units. Said ape insulators also have an upper metal attaching cap 160@ provided withl spaced lugs 102@ which are norinal to the lower tongue 148. A plate 122@ is secured to thek lower 24a by means of bolts 1245i and has a central depending tongue 126@ which lies between the lugs 102m and .is piv- K otally connected therewith by a 'pin 12?(2.

; gations 152 at their upper and lower ends rebars 142 yond the core structure. An insulating plate n 156 on which the lower end of the outer tube 151 rests is supported above the lower leg oftheV core 10a by means of'a washer 158 which rests upon said lower leg and surrounds the right-hand leg of the core beneath said plate. The plates 22a are provided with .outstanding flanges 24a one orp which supports a pair of insulating bushings 160 and 162. The terminal leads of said transformer secondary are'broughtl out through' one of Vsaid bushings as the bushing 162 and are adapted to be connected with 'the low tension control. circuit. 'A terminal lead 166 of said transformer primary isV extended through said other bushing 160 and is adapted to be connected to ground. The other terminal lead 168 ot said 'transformer primary is brought out through the casing wall 128 through an outwardly and downwardly iii-v clined insulating bushing 170.' VSaid bushing is secureddetachably in a weather tight inan-k et t' *nl "tl Afll128b ner to dne outside or ne casing wa y means of a bolted'sleeve 17 2 and is provided'.

at its outermost end with a metal cap 174 liaving'an externally screw-threaded neck 176.` 'lheplead 168 passes through several layers of'packing material 178 disposed within an internally screw-threaded cap 180 through which Vsaid lead extends and' which' is screw-threaded onto said neck 176 and compresses saidpacking about the lead 168.

The core structures of the several n iinpedance units each carry a multi-turn reactance winding 76a, which is insulated from theA core by means of telescoping inner and outer porcelain tubes 182 and 184, the latter of which carries the winding 76a externally thereof. The outermost tube 184 is supported above the core structure by means of an insulating disc V186 and a lower insulating washer 188 both of which are loosely threadcd over the right-hand leg oi' the core. The innermost tube 182 is formed with an enlarged corrugated upper end `portion 190 which overlies and rests upon the upper end or the outer tube 184 and supports said inner tube g" and said'outerniost tube has a similar corr gated lower end portion 191 which constitutes a support for the reactance winding The upper terminal lead 192 of said reactance winding is brought out through the casing wall 128 through a downwardly and outwardly extended bushing 194 which is similar inconstruction to the bushing 170,

or the transformer unit above. described.

The lower terminal of said winding is connected with the lead 1192 of the next Ylower impedance unit, or in the case of the lowermost impedance unit with the lead 168 of the transformer primary winding. The lead 192 or 168, as the case may be, extends through an insulating bushing which passes through one of the Loutstanding flanges 24e of the lower leg of thev core structure.

The space within the housing is adapted to be lilledwith a normallysolid insulating 196 which introduced into the housing in a heated and liquid state and which occupies the housing to a point below the core structure therein. For the purpose of filling the units they are inverted during the process of pouring in the compound and until the compound has set.

ln Fig. Ll a modied construction for an impedance unit is shown in which the multiturn winding 76?) is wound in two parts 198 2 `r1nd 200 which are insulated from the vertical leg of core 10b by a pair of upper and lower axially aligned and vertically spaced porcelain tubes 212 and 204, each porcelain tube having a winding carried externally thereof. 25 Said lower tube which rests on the core structure at its bottom end is provided with an enlarged and externally corrugated portion 206 at its lower end adjacent the core structure on which the reactance winding 200 is "supported in spaced relation with the core. The upper tube 202 has a similar enlarged portion 208 at its upper end which determines the upper position which the winding 198 can occupy. The space between the conyfronting end faces of said tubes 202 and 204 is occupied by an insulating' washer 210 which is carried by the vertical core leg and which centers an a nular insulating cylinder 212 which rests upon the upper end of the winding 200 and constitutes a support for the upper winding 198. The transformer can also be constructed in this manner, if desired.

Said reactance windings 198 and 200 have their common intermediate terminal leads 214i electrically connected together' and to said core structure 102) by means of a lug 216 which is secured to the core by a bolt 218, thus giving the core a potential which is inermediate that of the end terminals 220 and of said upper and lower coils respectively. Consequently the core need be insulated for a voltage representing one-half the combined voltage drop across the react-ance coils. As in the modification shown in Figs. 1 and the portion of the winding which is at liest potential is adapted to be located adjacent the enlarged corrugated end of the To this end the coils are 10j componi ressively beginning adjacent the ensd portions of the tubes and continuing axially along the tubes to the confronting ends thereof at which the intermediate termi-v nais of the coils are located. In this manner those portions of the winding which differ greatest from the potential of the core are located adjacent the enlarged ends of the tubes where they are most eifectively in- 7G sulated from the core. This construction of insulating shells permits the coils to be formwound and thereafter slipped upon the shells and thus provides an arrangement that can be economically manufactured.

Where it important te have the second ary voltage of the control circuit as nearly as pc ble in phase with the line voltage, the reactance windin frs may be composed of a high resistance wire which has the effect of correcting to a large degree the variation in the phase angle of the low tension secondary and high tension voltages.

Various modifications may be made in the construction without departing from the scope of the invention.

l c aim:

1. high tension suspension former comprising a st ng units eacn including a core strn-n 1 prising a magnetic circuit having vertical and upper and lower horizontal legs, a winding s rrounding vertical c rc structure and insulated the weatherproof housing oncle ing, and means for suspend1 from another comprising an pending member which is connecter`L lower horirontal leg of the upper cere and the upper horizontal leg of the next lower core and electrica ly insu-.lates said cores from each other.

2. An electromagnetic unit for a h' sion suspension type transformer core structure comprising a closed magnetic circuit, an insulating tube surrour 1 a leg' of said core having an outstanding per. flange at one end thereof, a by said tube and insulated f nal leads and having the high t thereof located adjacent the a: low tension lead locac adjacent 'the unllanged end of said tube, a .'featherproof housing enclosing said winding, and means for pendently supporting said unit by said core.

3. An electromagnetic unit 'c sion suspension type t a core structure compr circuit, an insulating tub tical leg of said core having a caiL e, an insulating shell conce spaced from said tube havin@ terminated beneath the ing` located in the annula sai-.l tube and shell, ar-.d for said unit attached to l core l. An electromagnetic unit for e sion suspension type transforme:

y 12e c .nirroun ding a ver-- outst and inc; ic with and.

- Vlegfof'said core having an outstanding corelstructure comprising a closed magnetic circuit, an'msulatmg tube surrounding a vertical leg of said core having an outstanding Vcape adjacentits upper end, a winding sur- 'Y having its upper end terminated beneath and closely adjacentthe lower Vface of said cape, and attaching means carried Vby the upper leg of said core structure for supporting said unit pendently from a high tension line.

6. In a high tension suspension type transformervincluding plurality of interconnected electromagnetic units, a transformer unit including a continuous core structure comprising a closed magnetic circuit, insulating tubes surrounding a vertical leg ofk said core vhaving end capes, primary and secondary windings carried by said insulatingtubes adjacent the capes thereof, a weatherroof housine for said windings, and means b 1 to support said unit pendently by said core structure. Y

7. In a high tension suspension type transformer including al plurality of interconnected electromagnetic units, a transformer unit including a continuous core structure comprising closed magnetic circuit, spaced inner and outer concentric insulating tubes surrounding a leg of said core, secondary and primary windings carried by -said inner and outer tubes respectively and insulated from the core by said tubes, said inner tube having an integral outstanding cape at its upper end which overlies the upper end of said outer tube and said outer tube having a cape which overlies said primary winding, and an insulating shell surrounding said primary winding having its upper end terminated beneath the cape of Y said outer tube.

8. In al high tension suspension type transformer including a, plurality of interconnected electromagnetic ,units, a transformerV unit including continuous core structure' comprising a closed magnetic circuit, spaced inner and outer concentric insulating tubessurrounding a vertical leg of vsaid core, secondaryand primary windings surrounding said tubes and insulated by said tubes from said core, said inner tube having an integral outstanding flange which overlies said secondary winding and the upper endof said outer tube andsaid outer tube having an outstanding flange which overlies said primary winding, an lnsulating tube surrounding said primary winding and concentric with said tubes having its upper end terminated beneath the flange of said outer tube, saidrprimary and secondary windings having leads extended downwardly in the spaces between said tubes, an insulating compound occupying the spaces beneath the cape of said first tube, said second tube having an outwardly directed cape adjacent its upper end,a primary winding surrounding said second tube beneath said cape, and an insulating shell enclosing said primary winding havin@ its upper end terminated beneath, the outwardly extended cape of said second tube, said primary winding having a terminal lead extended through said shell beneath the cape of said second tube. Y f

10. In a high tension suspension type transformer including a plurality of interconnected electromagnetic units, a vtransformer unit including a continuous core structure comprising` a closed magnetic circuit, an inner insulating tube extended along one leg of said core having an outwardly and downwardly directed cape at its upper end, a secondary winding surrounding said tube beneath said cape, an outer insulating tube surrounding said secondary winding and terminating at its upper end beneath the cape of said inner tube, said outer tube having an integral outwardly and downwardly directed cape adi acent the upper end thereof, a primary winding surrounding said outer tube beneath the cape thereof, an insulating shell enclosing said primary winding having its upper end terminated beneath the cap of said outer tube,'oppositely directed outstanding flanges carried by the upper leg of said core, and means to suspend said unit including clamping mea-ns having detachable connection. with said flanges.

ll. ln a high tension suspension type transformer including a plurality of interconnected electromagnetic units. a transformer unit including a continuous core structure comprising` a closed magnetic c1r' cuit, an innerinsulating tube extended on a vertical leg of said core structure having an annular outstanding flange at its upper end formed with an annular groove in its lower face, an outer insulating tube concentric with said inner tube having its upper end located within said annular groove and having an annular outstanding flange adjacent the upper end thereof, an insulating shell surrounding and concentric with said tubes having its upper end terminated beneath the flange of said outer tube, a secondary winding located in the space between said inner and outer tubeshaving a terminal extended downwardly in the space between said tubes, a primary winding disposed in the space between said outer tube and shell and having a terminal lead extended downwardly in the space therebetween, said primary winding also having a second terminal lead which extends through said shell beneath the flange of said outer tube, and an insulating compound disposed within the spaces between said inner and outer tubes and between said outer tube and shell.

12. In a high tension suspension type transformer including a plurality of interconnected electromagnetic units, a transformer unit including a continuous core struct-ure comprising a closed magnetic circuit, an inner insulating tube extended on a vertical leg of said core having an outstanding flange at its upper end, a secondary winding surrounding said inner tube and located beneath said flange, an outer insulating tube concentric with said inner tube having its upper end terminated beneath the flange of said inner tube and having an outstanding flange adjacent its upper end, a primary winding surrounding said outer tube beneath the flange hereof, a cylindrical shell surrounding said primary winding having its upper end terminated beneath the flange of said outer tube, said core having a laterally extended lower leg which constitutes the support for said tubes and said shell, said lower leg including an outstanding flange having insulating bushings extended therethrough one of which projects upwardly into the space between said tubes and the other of which projects upwardly into the space between said outer tube and shell, terminal leads for said primary and secondary windings extended downwardly through said bushings, and means having a connection with the upper leg of said core for suspending said unit.

13. In a high tension suspension type transformer including a plurality of interconnected electromagnetic units, a transformer unit including a continuous core structure comprising a closed magnetic circuit, an inner insulating tube extended on a leg of said core having an outwardly extended annular flange at its upper end which is formed with an annular recess in its lower lace, an outer insulating tube surrounding and spaced from said inner tube having its upper end terminated within said recess, said outer tube having an outwardly extended flange adjacent its upper end, an external insulating shell surrounding and spaced from said outer tube and having its upper end terminated within the confines of the flange of said outer tube, secondary and primary windings located in the spaces between said inner and outer tubes and said outer tube and shell respectively, a pair of side plates secured to the lower leg of said core and extended laterally beneath. said tubes and shell and constituting a support for the lower ends thereof, one of said side plates having an outstanding flange, said secondary winding having a terminal lead which is extended downwardly below said core structure, and an insulating bushing carried by said flange through which said lead is extended.

14. In a high tension suspension type transformer' including a plurality of interconnected electromagnetic units, a transformer unit including a continuous core structure comprising a closed magnetic circuit, an insulating tube surrounding a vertical leg` of said core, a secondary winding surrounding said tube, an outer and concentric tube surrounding said secondary winding, a primary winding surrounding said outer tube, an insulating cape carried by said inner tube forming a closure for the space between said tubes, said outer tube having a downwardly and outwardly directed flange adjacent its upper end, an insulating shell surrounding said primary winding having its upper edge terminated beneath said flange, a pair of side plates carried by the upper leg of said core having oppositely and outwardly directed flanges, means to suspend said unit includin,r attaching means having a detachable connection with the flanges of said side plates, a pair of side plates carried by the lower leg of said core having integral projections which extend beneath and constitute the support for said tubes ann shell, at least one of said lower side plates having an outstanding flange, terminal leads of said windings extended downwardly below said core structure, and insulating bushings carried by said flange through which said leads are extended.

15. lIn an electromagnetic unit for a high tension suspension type transformer including a plurality of interconnected suspension units, the combination of a continuous core structure which constitutes a closed magnetic circuit, an insulating tube surrounding avertical leg of said core having an annular outstanding cape at its upper end, a winding surroundinff' said tube beneath said cape, an insulating suell .surrounding` said winding having its upper end terminated beneath said cape and its lower end terminated below said winding, pairs of opposed side plates carried ssi by the yupper and lower'legs of said core having oppositely directed outstanding flanges, and meansy having a detachable connection with the flanges of said upper and lower legs 15 ior connecting said unit with adjacent upper and lower units. Y f

lh. ln aV high tension suspension type transformer including a plurality of interconnected electromagnetic units, a trans- Il() yformer `unit comprising a continuous core structure, a secondary winding surrounding and insulated from a vertical leg of said core a-ndspaced apart from the upper and lower thereof, a pair of telescoping inner and 1,5-` outer concentric tubes surrounding said secondary winding, said inner tube having an enlargedV upper end portion which overlies the upper end of saidouter tube and said outer tube having an enlarged lower end portion, and aY piniary winding surrounding said outer tube between the enlarged end portions of said tubes. Y

l?. ln a high tension suspension type transformer including a plurality of-inter- 253 sonnected electromagnetic units, a 'transformer unit comprising a continuous core structure, a secondary winding located on a vertical leg or" said core and insulated from said core, inner and outer telescoping insulatlng tubes surrounding said secondary winding, said outer tube having an enlarged corrugated lower end portion which is supported by the lower leg o1 said core and said in-` ner tube having an enlarged corrugated up- 351er end portion which rests upon the` upper end oit' said outer tube, a primary winding surrounding said tubes between the enlarged ond portions thereof, and a weatherproot1 housing enclosing and carried by the upper 40,"."eg of said core and enclosing said transformer windings.

18. ln a high tension suspensionV type transformer including a plurality of interconnected electromagnetic units, a transjif'oriner unit comprising a continuous core structure, a secondary winding located on a vertical leg of said core and insulated from said core, inner and outer telescoping insulating tubes surrounding` said secondary '.vinding, said outer tube having an enlarged corrugated lower end portion which is supj ported by the lower leg ofV said core and said inner tube having an enlarged corrugated upper end portion which rests upon the up- V per end ot said outer tube, a primary winding surrounding said tubes between the enlarfred'end portions'thereof, a housing enclosing and spaced apart from said telescoping tubes, and insulating 'compound occupying the space within said housing.

19. In a high tension suspension type transformer including a plurality of interconnected electromagnetic units, a transformer unit comprising a continuous core structure, a secc-ndary winding located on a vertical leg of said core and insulated from said core, inner and outer telescoping insulating tubesv surrounding said secondary winding, ksaid outer tube having anenlarged corrugated lower end portion which is supported by tnelower leg of said core and said inner tube haring an enlarged corrugated upper end portion which rests upon the upper enc of said outer tube, a piiinary'winding irrounding said tubes between the enlarged end portions thereof, a metallic housing et closing said core structure transformer Vwindings, `said housing being open at the bottoni, teriifnal leads tor said windings extended downwardly through the open bottoni et said housing, a downwardly and outwardly directed insulating bushing extended through the 'side wall of said housing, and a terni-in l lead I said primary winding vextended through sa bushing. Y A y 20. In a high tension suspension typetiansformer including a pluralityY of intercon-l Asurrounding said outer tube above the lower enlarged portion thereof, a pair ot side plates Y carried by the upper leg of said core having oppositely and outwardly extended flanges, an open bottom housing enclosing said core structure including a cover wall which rests upon said flanges, said cover and flanges having aligned passages therethrough and said cover having integral upstanding necks surrounding the passages therein, an attaching member for supporting said unit comprising an attaching block having a recess in the lower face thereof within which said necks project, and clamping bolts extended through said attaching lock and the aligned passages in said cover and the flanges of said core.

2l. An electromagnetic unit for a high tension suspension type transformer including a continuous core structure, inner andouter telescoping insulating tubes surrounding a leg of said core, said outer tube having an enlarged lower end portion adjacent the lower leg of the Vcore and said inner tube having enlarged upper end portion adjacent the upper leg of said core, a winding surrounding said telescoping tubes between the enlarged end portions thereof, a housing enclosing said core and winding, an attaching means khaving connections with. said core structure at the upper and lower legs thereof ij'cr connecting said unit with adjacent upper and lower units.

22. An electromagnetic unit for a high tension suspension type transformer including a continuous core structure, inner and outer telescoping insulating tubes surrounding a leg of said core, said outer tube having an enlarged lower end portion adjacent the lower leg of the core and said inner tube having an enlarged upper end portion adjacent the upper leg of said core, a winding surrounding said telescoping tubes between the enlarged end portions thereof, attaching members having a connection with said core at the top and bottom thereof arranged to connect said unit with adjacent upper and lower units, and a housing enclosing said core structure and winding which is open at the bottom having a top closure therefor which is disposed between said core structure and the upper clamping member thereof.

23. An electromagnetic unit for a high tension suspension type transformer including a continuous core structure, inner and outer telescoping insulating tubes surrounding a leg of said core, said outer tube having an enlarged lower end portion adjacent the lower leg of the core and said inner tube having an enlarged u per end portion ad-l jacent the upper leg of, said core, a winding surrounding said telescoping tubes between the enlarged end portions thereof, pairs of opposed side plates carried by the upper and lower legs of said core structure having oppositely and outwardly directed fianges, upper and lower attaching members connected with the flanges of said upper and lower plates having provision for connecting said unit pivotally with the adjacent upper and lower units, a housing enclosing said core structure and winding which is supported by the flanges of said upper leg, an insulating bushing extended through a flange of said lower leg, a second insulating bushing extended downwardly and outwardly through a side wall of said housing, and terminal leads for said winding extended separately through said bushings.

24. In a suspension transformer, the combination of a string of electromagnetic units each comprising a magnetic core having top, bottom and side legs and a winding surrounding a leg of said core, the windings of the several units being connected electricalr ly in series, and suspension insulators interposed between and mechanically flexibly connecting the cores of adjacent units of the string, said insulators comprising insulating bodies having upper and lower metal attaching members carried by remote portions thereof, and means connecting said upper and lower attaching members pivotally with the bottom and top leg respectively of adjacent core structures.

25. Electrical apparatus comprising a GUSTAV E. JANSSON. 

